This is an Oblivion Gate from Elder Scrolls IV: Oblivion Remastered.
I am amazed nobody made this one before, so I did it myself using about 20 screenshots from the game itself.
"oblivion gate" and "portal" is the trigger word, but having helpers like "red sky" "fire" and may make it stronger.
Extras include daedric architecture such as citadels and the Oblivion Deadlands landscape.
"hellscape" "tower" "citadel" and "red lightning" may be effective in creating these objects